Fathers and sons, mothers and daughters: Sex-specific genetic architecture for fetal testosterone in a wild mammal

Testosterone plays a critical role in mediating fitness-related traits in many species. Although it is highly responsive to environmental and social conditions, evidence from several species show a heritable component to its individual variation. Despite the known effects that in utero testosterone exposure have on adult fitness, the heritable component of individual testosterone variation in fetuses is mostly unexplored. Furthermore, testosterone has sex-differential effects on fetal development, i.e., a specific level may be beneficial for male fetuses but detrimental for females, producing sexual conflict. Such sexual conflict may be resolved by the evolution of a sex-specific genetic architecture of the trait. Here, we quantified fetal testosterone levels in a wild species, free-ranging nutrias (Myocastor coypus) using hair-testing and estimated testosterone heritability between parent and offspring from the same and opposite sex. We found that in utero accumulated hair testosterone levels were heritable between parents and offspring of the same sex. Moreover, there was a low additive genetic covariance between the sexes, and a low cross-sex genetic correlation, suggesting a potential for sex-specific trait evolution, expressed early on, in utero.

Paternity share predicts sons' fetal testosterone

Multiple paternity is common in many species. While its benefits for males are obvious, for females they are less clear. Female indirect benefits may include acquiring 'good genes' for offspring or increasing litter genetic diversity. The nutria (Myocastor coypus) is a successful invasive species. In its native habitat, it is polygynous, with larger and more aggressive males monopolizing paternity. Here, using culled nutria we genetically examined multiple paternity in-utero and found a high incidence of multiple paternity and maintenance of the number of fathers throughout gestation. Moreover, male fetuses sired by the prominent male have higher testosterone levels. Despite being retained, male fetuses of 'rare' fathers, siring commonly only one of the fetuses in the litter, have lower testosterone levels. Considering the reproductive skew of nutria males, if females are selected for sons with higher future reproductive success, low testosterone male fetuses are expected to be selected against. A possible ultimate explanation for maintaining multiple paternity could be that nutria females select for litter genetic diversity e.g., a bet-hedging strategy, even at the possible cost of reducing the reproductive success of some of their sons. Reproductive strategies that maintain genetic diversity may be especially beneficial for invasive species, as they often invade through a genetic bottleneck.

Evolution of Embryo Implantation Was Enabled by the Origin of Decidual Stromal Cells in Eutherian Mammals

Mammalian pregnancy evolved in the therian stem lineage, that is, before the common ancestor of marsupials and eutherian (placental) mammals. Ancestral therian pregnancy likely involved a brief phase of attachment between the fetal and maternal tissues followed by parturition-similar to the situation in most marsupials including the opossum. In all eutherians, however, embryo attachment is followed by implantation, allowing for a stable fetal-maternal interface and an extended gestation. Embryo attachment induces an attachment reaction in the uterus that is homologous to an inflammatory response. Here, we elucidate the evolutionary mechanism by which the ancestral inflammatory response was transformed into embryo implantation in the eutherian lineage. We performed a comparative uterine transcriptomic and immunohistochemical study of three eutherians, armadillo (Dasypus novemcinctus), hyrax (Procavia capensis), and rabbit (Oryctolagus cuniculus); and one marsupial, opossum (Monodelphis domestica). Our results suggest that in the eutherian lineage, the ancestral inflammatory response was domesticated by suppressing one of its modules detrimental to pregnancy, namely, neutrophil recruitment by cytokine IL17A. Further, we propose that this suppression was mediated by decidual stromal cells, a novel cell type in eutherian mammals. We tested a prediction of this model in vitro and showed that decidual stromal cells can suppress the production of IL17A from helper T cells. Together, these results provide a mechanistic understanding of early stages in the evolution of eutherian pregnancy.

Non-model species deliver a non-model result: Nutria female fetuses neighboring males in utero have lower testosterone

Neighboring fetuses may impact their siblings in various respects, depending on their in utero location and sex. The effects of the intrauterine position (IUP) are widely studied in model organisms, especially laboratory bred murine strains that are characterized by short gestations and altricial offspring. In some species, the proximity to a male fetus and its higher circulating testosterone masculinizes neighboring female fetuses. In utero testosterone exposure might be manifested as higher testosterone concentrations, which contribute to a variation in morphology, reproductive potential and behavior. In this study, we examined the influence of neighboring an opposite sex fetus on testosterone levels in a feral animal model characterized by a long gestation and precocious offspring. Using necropsies of culled nutria (Myocastor coypus), we accurately determined the IUP and quantified testosterone immunoreactivity in fetal hair. We found that as expected, both male and female fetuses neighboring a male in utero had longer anogenital distance. However, females adjacent to males in utero showed lower testosterone levels than male fetuses, while testosterone levels of females without a male neighbor did not differ from those of males. This surprising result suggests an alternative mode by which local exogenous steroids may modify the local fetal environment. Our study emphasizes the importance of examining known phenomena in species with different life histories, other than the traditional murine models, to enhance our understanding of the evolutionary mechanisms that are driving sexual differentiation.

Cortisol advantage of neighbouring the opposite sex in utero

Population sex ratios naturally fluctuate around equality. It is argued that the production of an equal number of male and female offspring by individual parents should be favoured by selection, if all costs and benefits are equal. Theoretically, an even sex ratio should yield the highest probability for a fetus to be adjacent to a fetus of the opposite sex in utero. This may cause developmental costs or benefits that have been overlooked. We examined the physiological and developmental parameters associated with in utero sex ratios in the nutria (Myocastor coypus), an invasive wildlife species with a strong reproductive output. Using hair testing, we found that litters with even sex ratios had the highest average cortisol levels. Fetuses neighbouring the opposite sex exhibited longer trunks than those neighbouring the same sex, which might imply better lung development. Our results are the first, to our knowledge, to link intra-utero sex ratios and fetal cortisol and suggest that fetal cortisol might be a mechanism by which even sex ratios are maintained via developmental advantages.

MATERNAL DEPRESSION AND CHILD OXYTOCIN RESPONSE; MODERATION BY MATERNAL OXYTOCIN AND RELATIONAL BEHAVIOR

BACKGROUND

Maternal postpartum depression (PPD) carries long-term detrimental effects on children's well-being, yet the mechanisms of transmission remain unclear. One possible pathway of vulnerability involves the oxytocinergic (OT) system, which is transferred from mother to child via sensitive caregiving and is disrupted in PPD.

METHOD

A large birth cohort (N = 1983) of women were repeatedly assessed for depression from birth to 6 years. Utilizing an extreme case design, two matched cohorts were formed; mothers chronically depressed from birth to 6 years and nondepressed controls (N = 97, depressed = 41, nondepressed; N = 56). At 6 years, mothers and children underwent psychiatric diagnosis, urinary OT was assayed from mother and child before and after social contact, and mother-child interactions were coded.

RESULTS

Baseline OT and OT response of mother and child were interrelated and children of depressed mothers showed low baseline OT and attenuated OT response. Child OT response was negatively predicted by maternal depression, child Axis-I psychopathology, maternal expressed negative affect, and child social withdrawal. Interaction effect of maternal baseline OT and depression emerged. Slope analysis indicated that when maternal OT was medium or low, child OT response was negatively impacted by maternal depression. However, when maternal OT was high, child OT was unaffected, suggesting that maternal OT functionality buffers the effects of depression on the child.

CONCLUSION

Results suggest involvement of the OT system in the cross-generational transfer of vulnerability, as well as resilience, from depressed mothers to their children. Because the OT system is open to interventions that enhance maternal touch and contact, findings have important implications for targeted early dyadic inventions.

Structure at 2.6 A resolution of phenylalanyl-tRNA synthetase complexed with phenylalanyl-adenylate in the presence of manganese

The crystal structure of phenylalanyl-tRNA synthetase (PheRS) from Thermus thermophilus, a class II aminoacyl-tRNA synthetase, complexed with phenylalanyl-adenylate (Phe-AMP) was determined at 2.6 A resolution. Crystals of native PheRS were soaked in a solution containing phenylalanine and ATP in the presence of Mn(2+) ions. The first step of the aminoacylation reaction proceeds within the crystals, resulting in Phe-AMP formation at the active site. Specific recognition of the phenylalanine portion of the Phe-AMP is achieved by interactions of the phenyl ring of Phe-AMP with two neighbouring residues, Phealpha258 and Phealpha260. No manganese ions were observed within the active site; their role in the formation of the transition state may be assigned to a number of polar residues and water molecules. In the anomalous Fourier difference map, a divalent metal ion was detected at the interface of the alpha- and beta-subunits at a short distance from motif 3 residues participating in the substrate binding. A sulfate ion, which was identified on the protein surface, may mediate the interactions of PheRS with DNA. Visible conformational changes were detected in the active-site area adjacent to the position of the Phe-AMP, compared with the structure of PheRS complexed with a synthetic adenylate analogue (phenylalaninyl-adenylate). Based on the known structures of the substrate-free enzyme and its complexes with various ligands, a general scheme for the phenylalanylation mechanism is proposed.

The addition of paclitaxel to continuous infusion 5-fluorouracil is an active regimen for metastatic breast cancer

Metastatic breast cancer is commonly thought to be incurable. Treatment advances have resulted in increased response rates, although such responses are often more palliative than curative. A regimen of continuous infusion 5-fluorouracil (5FU) or continuous infusion 5-fluorouracil with paclitaxel was studied in patients with metastatic breast cancer and measurable disease. The induction therapy preceded high-dose ifosfamide, carboplatin, and melphalan in a phase I-II trial. Eighty-seven patients were enrolled in the trial. Forty-five received continuous infusion 5-fluorouracil as induction and 42 received 5-fluorouracil and paclitaxel. The single-agent, continuous infusion 5-fluorouracil cohort had one complete response (2%) and eight partial responses (18%). The combination continuous infusion 5-fluorouracil and 3-hour paclitaxel regimen produced four complete responses (10%) and 17 partial responses (40%). The combination regimen of continuous infusion 5-fluorouracil with bolus paclitaxel was well tolerated and with a 50% response rate, is an active regimen for women with metastatic breast cancer.

ICI 182,780 inhibits endogenous estrogen-dependent rat uterine growth and tamoxifen-induced developmental toxicity

To assess the effects of the steroidal antiestrogen ICI 182,780 on postnatal uterine development, female Sprague-Dawley rats were given s.c. injections of ICI 182,780 (0.1-100 micrograms/rat) on each of postnatal days (PND) 10-14. ICI 182,780 inhibited uterine growth, as measured by uterine weight, in a dose-dependent manner but had no effect on either uterine luminal epithelium hypertrophy or gland genesis. Immunohistochemical analysis revealed that ICI 182,780 (10 micrograms) markedly reduced uterine estrogen receptor (ER) immunoreactivity in all uterine cell types while tamoxifen (10 micrograms) increased ER immunoreactivity, most notably in the luminal epithelium. In addition, tamoxifen increased uterine weight and induced luminal epithelium hypertrophy but inhibited uterine gland genesis--outcomes also seen with synthetic estrogens such as diethylstilbestrol. To test the hypothesis that these effects are a consequence of the estrogen agonist activity of tamoxifen, rats were cotreated with ICI 182,780 (10 micrograms, PND 8-14) and tamoxifen (10 micrograms, PND 10-14). ICI 182,780 greatly reduced or completely blocked tamoxifen-induced uterine weight gain, luminal epithelium hypertrophy, tamoxifen-induced ER immunoreactivity, and the inhibition of uterine gland genesis. ICI 182,780 given daily on PND 1-5 did not alter PND 5 uterine weight or uterine differentiation on PND 26. We conclude that postnatal exposure to ICI 182,780 does not affect uterine growth or differentiation at an age when the uterus is not dependent on estrogen for growth, i.e., PND 1-5, but does inhibit later endogenous estrogen-dependent uterine growth. The blockade of tamoxifen-induced uterine developmental alterations by ICI 182,780 demonstrates that these tamoxifen effects result from its estrogen agonist activity.

Comparison of direct interview and family history diagnoses of alcohol dependence

Using data from The Collaborative Study on the Genetics of Alcoholism, we compare direct interview diagnoses of alcohol dependence to those obtained by history from family members. Using a requirement of three or more positive implications by history, the specificity, sensitivity, and positive predictive values are 98%, 39%, and 45%, respectively. A logistic analysis found the gender of the relative and alcoholism in the informant to be significant, but not the gender of the informant. The partial odds ratio of a diagnosis at interview associated with a positive family history diagnosis was 13.6. The relationship between the informant and relative was significant, with negative reports from an offspring or mate more influential than a negative report from a parent or second-degree relative. We derived a recursive equation to combine a variable number of family history reports, wherein the probabilities associated with a single report are computed from the logistic analysis. This permits the use of family history information both as a proxy for an uninterviewed relative, as well as a second source of information to be used in the analysis of genetic family data.

Changing incidence and management of abrupt closure following coronary intervention in the new device era

Abrupt closure of the dilated segment occurs in approximately 4 to 7% of cases following conventional percutaneous coronary angioplasty. Additional balloon angioplasty reverses roughly 40% of these closures, to yield an overall 1.6 to 3.4% rate of emergent surgery. The impact of new devices on the incidence and reversal rate of abrupt closure has not been examined. Abrupt closure occurred in 80 (4.2%) of 1,919 consecutive coronary angioplasties performed in our single center, 389 (20%) of which were performed using newer interventions (208 Palmaz-Schatz stents, 170 directional coronary atherectomies, and 11 elective laser balloon angioplasties). Abrupt closure was less frequent following newer coronary interventions (1.8%) compared to standard balloon angioplasty (4.9%, P < 0.01), possibly reflecting case selection. When abrupt closure did occur, percutaneous rescue was successful in 53 (66%) patients, including 42 (53%) who were rescued using standard or perfusion balloon angioplasty, and 11 (13%) who were rescued using laser balloon balloon angioplasty after failure of additional angioplasty attempts. Medical therapy alone was used in 8 (10%), while emergent coronary bypass surgery was performed in 18 (23%), yielding an overall emergent surgery rate of 0.9%. Q-wave myocardial infarction was significantly less frequent (0.2%) following percutaneous rescue, compared to either medical therapy (25%) or emergent surgery (33%, P < 0.001). In our catheterization laboratory, use of these 3 new coronary interventional devices coincides with a trend towards a lower incidence of abrupt closure, a higher percutaneous rescue rate with reduced incidence of myocardial infarction, and a lower emergent bypass surgery rate.

Impaired elastic matrix development in the great arteries after ablation of the cardiac neural crest

The cells that form the aorticopulmonary septum in the avian embryo have been shown to be similar to the cells that form the walls of the great vessels in two ways: both are derived from the cardiac neural crest and both are able to synthesize an elastogenic matrix in the early embryo. Because of these similarities, and because ablation of the cardiac neural crest causes congenital defects of the outflow tract that are related to failure of proper septation, it was hypothesized that such an ablation also would cause the walls of the great vessels to be defective. The purpose of this study was to compare the elastic matrix in the mediae of the great vessels of normal embryos with those from which the cardiac neural crest had been ablated. The results show that the elastic matrix in the great vessels of the experimental embryos was impaired 1) in the rate of downstream propagation of the initiation of elastogenesis among younger embryos, incubation days 4-8 and 2) in the spatial configuration of the elastic matrix among the older embryos, incubation days 16-20. These results may provide a biological explanation for the elastin defect that affects the pulmonary artery of many patients with cyanotic congenital heart defects.

The familial transmission of bipolar illness

As part of the National Institute of Mental Health Collaborative Program on the Psychobiology of Depression study, data were collected on 2225 first-degree relatives of 612 probands. We analyzed 187 families of bipolar patients (149 probands with a diagnosis of bipolar I disorder and 38 with a diagnosis of schizoaffective, manic subtype). Using traditional genetic methods, the morbid risk of bipolar illness in relatives was found to be 5.7% in the relatives of bipolar probands as contrasted with 1.1% in the relatives of probands with major depression. These values compared closely with those obtained using survival analysis. Relatives of probands with early onset were found to have a greater risk than relatives of probands with late onset. The sex of the relative, the sex of the proband, or the subtype of the proband (bipolar I or schizoaffective bipolar) did not influence the risk in the relative. The age at onset was found to be accelerated with birth cohort, with individuals born in more recent cohorts having an earlier onset. Multifactorial analysis found significant heterogeneity for sex-specific sibling correlations (with the brother-sister correlation smaller than the same-sexed correlations), and path analysis estimated transmissibility of liability to be 71%. The mixed model, which allows for a single major locus with a multifactorial background, gave evidence for the presence of a major locus when controlling for the effects of birth cohort and age at onset. However, this evidence is tempered when comparing the mixed model with a more general transmission model.

The modulation of transmitter release in motor nerve endings varies with the type of muscle fiber innervated

Electrophysiological studies of synaptic transmission in mammalian muscles revealed substantial differences between neuromuscular synapses associated with fast versus slow-twitch motor units. Synapses of fast units exhibited much higher tetanic and post-tetanic potentiation of neurotransmitter release than those of slow units. On the other hand, the tetanic potentiation of slow units increased faster as a function of the frequency of activation than that of fast units. These differences suggest a possible specialization of neuromuscular synapses with the type of motor units they are associated with.

Psychiatric adolescent inpatients: eight- to ten-year follow-up

Seventy-seven adolescent psychiatric inpatients, whose index hospitalization was at a mean age of 16, were followed up for eight to ten years after discharge. The important findings at follow-up were as follows. Twelve patients had bipolar affective disorder and were severely disabled (of these, 11 had a long-term clinical course and three committed suicide). Sixteen patients had unipolar depression: five had one depressive episode and were well throughout the follow-up period, one patient had many episodes with complete remissions, and the remaining ten patients had only partial remissions and their impairment of functioning corresponded to the severity of their symptoms. One of the ten committed suicide. Eighteen (23%) patients were psychiatrically well and functioned adequately throughout the follow-up period. Five had primary depressions, five had undiagnosed psychiatric illness, and eight were diagnosed as not having a psychiatric disorder.

Psychiatric disorders among professional women

A group of 111 women physicians and 103 women PhDs, selected from the general community, were studied for the presence of psychiatric illness. Fifty-one percent of the MDs and 32% of the PhDs were diagnosed as having primary affective disorder (P less than .01). Other psychiatric disorders were found in less than 10% of each group. Depression among the psychiatrists was significantly more common (73%) than among the other physicians (46%). More than 50% of all the women reported prejudice in training or employment, and depressed subjects reported prejudice more often than well subjects. The presence of children and depression were shown to disrupt a woman's professional career. The finding of a high prevalence of affective disorder among women physicians is consistent with the reported excessive suicide risk for this group.

Quantitative aspects of computed tomography of the blood and cerebrospinal fluid

Computed tomographic (CT) scans of fresh and coagulated blood in vitro as well as calcium and iron solutions demonstrate that the increased absorption seen in hematomas is primarily a reflection of hemoconcentration: calcium plays essentially no role in this increased absorption, while iron makes a minimal contribution. In vitro studies of cerebrospinal fluid (CSF) indicate that CT scanning is insensitive to pathological elevations of CSF protein.